# Five G Planet **URL:** \ **Category:** Factual Questions\ **Created:** [September 30, 2010, 1:14pm UTC](https://boards.straightdope.com/t/five-g-planet/555593 "2010-09-30T13:14:13Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![bup](https://avatars.discourse-cdn.com/v4/letter/b/6bbea6/32.png) [@bup](https://boards.straightdope.com/u/bup)\ **Post date:** [September 30, 2010, 3:20pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/21 "2010-09-30T15:20:46Z")
Sure, a 37-earth-day year sounds all great, until you realize that from \*their \*planet, earth is 197 light years away… ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 30, 2010, 3:30pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/22 "2010-09-30T15:30:07Z")
> [@Kinthalis](#): > > 20+ light years away. How long would it take the fastest probe we could launch say in 10 years with the best tech we have (or are likely to have then)? > > I’m guessing something disappointing like centuries… The fastest spacecraft made so far is Voyager I. Due to gravitational assists it is chugging along at 38,600 miles per hour. This planet is 120 trillion miles away. So, it’d take Voyager I (if it was heading that way) 354,886.79 years to get there. So, a bit more than a few centuries. 😉 ---
**Author:** ![Mr.Excellent](https://avatars.discourse-cdn.com/v4/letter/m/f19dbf/32.png) [@Mr.Excellent](https://boards.straightdope.com/u/Mr.Excellent)\ **Post date:** [September 30, 2010, 3:33pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/23 "2010-09-30T15:33:09Z")
> [@Whack-a-Mole](#): > > > [@](#): > > > > “It’s not a very interesting name and it’s a beautiful planet,” Vogt said. Unofficially, he’s named it after his wife: “I call it Zarmina’s World.” > > > > SOURCE: [http://news.yahoo.com/s/ap/20100929/ap\_on\_sc/us\_sci\_new\_earths](http://news.yahoo.com/s/ap/20100929/ap_on_sc/us_sci_new_earths) Okay, that’s way too sappy. Still needs a cooler name. How about Hephaestus? A hot, rocky, metal-rich world - seems to fit. ETA: Or, if we want something more to-the-point and less Greco-Roman-ey: Why not Longshot? ---
**Author:** ![Wendell\_Wagner](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@Wendell\_Wagner](https://boards.straightdope.com/u/Wendell_Wagner)\ **Post date:** [September 30, 2010, 3:33pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/24 "2010-09-30T15:33:53Z")
Let’s assume that two planets have the same density but planet X has n times the mass of planet Y. (This is already a simplification, since we don’t know the densities, but we’ve got to simplify somewhere.) If two spheres have the same density but one has n times the mass of the smaller one, that means that it also has n times the volume of the smaller one. This means that it has n^(1/3) (that is, the cube root) of the diameter of the smaller one. The gravity of a planet on its surface is determined by the mass of the planet divided by the square of the diameter of the planet. So the gravity on the surface of planet X is n divided by n^(2/3), which is n^(1/3), of the gravity on the surface of planet Y. So if this planet in the news story is 5 times the mass of Earth and has the same density as Earth, it will have 5^(1/3) = (approximately) 1.7 times the surface gravity of Earth. ---
**Author:** ![Mr.Excellent](https://avatars.discourse-cdn.com/v4/letter/m/f19dbf/32.png) [@Mr.Excellent](https://boards.straightdope.com/u/Mr.Excellent)\ **Post date:** [September 30, 2010, 3:34pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/25 "2010-09-30T15:34:13Z")
> [@Whack-a-Mole](#): > > > [@Kinthalis](#): > > > > 20+ light years away. How long would it take the fastest probe we could launch say in 10 years with the best tech we have (or are likely to have then)? > > > > I’m guessing something disappointing like centuries… > > The fastest spacecraft made so far is Voyager I. Due to gravitational assists it is chugging along at 38,600 miles per hour. > > This planet is 120 trillion miles away. > > So, it’d take Voyager I (if it was heading that way) 3,108,808,290 years to get there (3 billion years). > > So, a bit more than a few centuries. 😉 That’s with Voyager’s tech, though. We can do much better. [Project Orion (nuclear propulsion) - Wikipedia](http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)) ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 30, 2010, 3:51pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/26 "2010-09-30T15:51:13Z")
> [@Mr.Excellent](#): > > That’s with Voyager’s tech, though. We can do much better. [Project Orion (nuclear propulsion) - Wikipedia](http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)) Note I corrected my calculation (that is how many hours it takes). My bad. Still, 350,000+ years is a bit long anyway. I am sure we could do better if we really wanted to but still…achieving anything that could get there in even under a thousand years (much less a more palatable 100) is either beyond our tech or would be so colossally expensive to build no one would bother. Add in a radio that could send a message back that we could hear. I would think the dish would have to be bigger than Arecibo with tons of power to have a chance. Something that big would be problematic on a spaceship we could conceivably build. ---
**Author:** ![Paul\_in\_Qatar](https://avatars.discourse-cdn.com/v4/letter/p/ccd318/32.png) [@Paul\_in\_Qatar](https://boards.straightdope.com/u/Paul_in_Qatar)\ **Post date:** [September 30, 2010, 3:55pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/27 "2010-09-30T15:55:57Z")
What does ‘tidal-locked’ mean? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 30, 2010, 3:58pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/28 "2010-09-30T15:58:08Z")
> [@Mr.Excellent](#): > > That’s with Voyager’s tech, though. We can do much better. [Project Orion (nuclear propulsion) - Wikipedia](http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion))) Note in your link, assuming it works and gets max speed, it says it would take 100 years to go 10 light years. So 200 years to get to this planet. It would have to be a generation ship if we wanted to send humans. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 30, 2010, 3:59pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/29 "2010-09-30T15:59:11Z")
> [@Paul\_in\_Qatar](#): > > What does ‘tidal-locked’ mean? One face always points towards the sun (or in the case of our moon which is tidally locked to the earth one side of the moon always points at the earth). Eventually the earth will become tidally locked as well but not for billions of years. ---
**Author:** ![Mr.Excellent](https://avatars.discourse-cdn.com/v4/letter/m/f19dbf/32.png) [@Mr.Excellent](https://boards.straightdope.com/u/Mr.Excellent)\ **Post date:** [September 30, 2010, 4:05pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/30 "2010-09-30T16:05:18Z")
> [@Whack-a-Mole](#): > > > [@Mr.Excellent](#): > > > > That’s with Voyager’s tech, though. We can do much better. [Project Orion (nuclear propulsion) - Wikipedia](http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion))) > > Note in your link, assuming it works and gets max speed, it says it would take 100 years to go 10 light years. So 200 years to get to this planet. > > It would have to be a generation ship if we wanted to send humans. Good grief - why would we send humans? Anything men can do, machines can do better - machines can do anything better than you. 🙂 And actually, the 200 years figure might be optimistic - if it took a while to get up to 5% of light-speed, and we also wanted to slow down enough to do detailed observations, we couldn’t actually spend long going that fast. But who cares? The only time that matters is the time it takes to build and launch the probe - after that, whether it takes 200 or 400 years to get to its destination, it’s still going to be long after we’re all dead. It only happens if there’s the political will to say “This we do for all mankind, not for ourselves.” But that’s happened historically - with cathedrals, the Pyramids, and so on. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 30, 2010, 4:13pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/31 "2010-09-30T16:13:14Z")
> [@Mr.Excellent](#): > > Good grief - why would we send humans? Anything men can do, machines can do better - machines can do anything better than you. 🙂 If the earth was doomed from a rogue star headed our way or something. 😉 > [@](#): > > And actually, the 200 years figure might be optimistic - if it took a while to get up to 5% of light-speed, and we also wanted to slow down enough to do detailed observations, we couldn’t actually spend long going that fast. > > But who cares? The only time that matters is the time it takes to build and launch the probe - after that, whether it takes 200 or 400 years to get to its destination, it’s still going to be long after we’re all dead. It only happens if there’s the political will to say “This we do for all mankind, not for ourselves.” But that’s happened historically - with cathedrals, the Pyramids, and so on. I considered the acceleration/deceleration and it does not amount to much. Again your link says 36 days at 1g acceleration to reach 10% light speed. I presume another 36 days to slow down at the other end so fairly insignificant compared to total flight time. Considering the cost of the Space Shuttle I can only imagine a space ship such as this would be hugely expensive. Also, while it might look good on paper from there to a workable ship is quite a leap. We could probably do it if we really, really wanted to but I wouldn’t hold your breath waiting for it. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [September 30, 2010, 4:20pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/32 "2010-09-30T16:20:39Z")
> [@Mr.Excellent](#): > > That’s with Voyager’s tech, though. We can do much better. Forgot this part. Seems we have not improved on that at all. The New Horizons space probe to Pluto was launched in 2006 and it is a little slower (not much) than Voyager. Most spaceprobes seem to be in this speed range. Maybe we could but we don’t (guessing it is a cost/benefit tradeoff such that little boosts in speed cost way too much to be worthwhile). ---
**Author:** ![Kilmore](https://avatars.discourse-cdn.com/v4/letter/k/a6a055/32.png) [@Kilmore](https://boards.straightdope.com/u/Kilmore)\ **Post date:** [September 30, 2010, 4:25pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/33 "2010-09-30T16:25:55Z")
Well, now that we have a place to go, there’s going to be a lot more thought and energy put towards getting there. 20 light years is good. There’s at least a bit of hope of exploring the place at 20 light years. If it was something like 40 thousand light years away there would be no real incentive. ---
**Author:** ![Chessic\_Sense](https://avatars.discourse-cdn.com/v4/letter/c/7c8e57/32.png) [@Chessic\_Sense](https://boards.straightdope.com/u/Chessic_Sense)\ **Post date:** [September 30, 2010, 4:40pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/34 "2010-09-30T16:40:30Z")
It’s cool, guys. The aliens found out about us 800 years ago and launched a probe soon after. Prepare to be probed. They don’t do this for themselves, they do it for zorkkind. BTW, it’s easy to get things to travel at c. My radio does it every day. Maybe it’s time to start thinking of something (serious) to broadcast to that planet. ---
**Author:** ![marshmallow](https://avatars.discourse-cdn.com/v4/letter/m/df705f/32.png) [@marshmallow](https://boards.straightdope.com/u/marshmallow)\ **Post date:** [September 30, 2010, 4:41pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/35 "2010-09-30T16:41:56Z")
Scientific American had an interesting article on Super Earths awhile back. Not for free though. > [@Whack-a-Mole](#): > > Add in a radio that could send a message back that we could hear. I would think the dish would have to be bigger than Arecibo with tons of power to have a chance. Something that big would be problematic on a spaceship we could conceivably build. Not to mention who’s going to record the results? We better leave a post-it note for humanity in 500 years, assuming anyone is still around, let alone anyone who can understand English. Or can even detect and interpret the signal which by that time will be seriously outdated technology wise. Maybe we could set up a recording device on the moon with a technological Rosetta stone. ---
**Author:** ![FluffyBob](https://avatars.discourse-cdn.com/v4/letter/f/ecb155/32.png) [@FluffyBob](https://boards.straightdope.com/u/FluffyBob)\ **Post date:** [September 30, 2010, 5:01pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/36 "2010-09-30T17:01:06Z")
I imagine the mattress and lounge furniture technology of any civilization from this world would be far in advance of ours. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [September 30, 2010, 6:46pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/37 "2010-09-30T18:46:27Z")
> [@Wendell\_Wagner](#): > > So if this planet in the news story is 5 times the mass of Earth and has the same density as Earth, it will have 5^(1/3) = (approximately) 1.7 times the surface gravity of Earth. If it’s that easy to calculate, why hasn’t anyone posted that 1.7 g figure earlier in the thread… 🙂 ---
**Author:** ![Kinthalis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kinthalis/32/16084_2.png) [@Kinthalis](https://boards.straightdope.com/u/Kinthalis)\ **Post date:** [September 30, 2010, 7:07pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/38 "2010-09-30T19:07:12Z")
So it won’t happen for centuries in the first place, and even then it’ll be centuries before we hear anything back in terms of observations from a probe. Stephen Hawkins is still working on that hyper drive, though, isn’t he? ---
**Author:** ![Stranger\_On\_A\_Train](https://avatars.discourse-cdn.com/v4/letter/s/13edae/32.png) [@Stranger\_On\_A\_Train](https://boards.straightdope.com/u/Stranger_On_A_Train)\ **Post date:** [September 30, 2010, 8:15pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/39 "2010-09-30T20:15:32Z")
> [@Mr.Excellent](#): > > I wanna send a probe! This is neat! Heck - if we built a probe on the old “Orion” design (set off nukes behind a giant pusher-plate for acceleration), it’s not crazy to hope we could hit maybe 5% of light-speed. [thread=477444]Do we have the technology to build a probe to visit another star?[/thread] The answer: not by a long shot. Perhaps some day, but not today, not next year, and probably not for decades (at least 10-20 years of concerted effort). Stranger ---
**Author:** ![Mr.Excellent](https://avatars.discourse-cdn.com/v4/letter/m/f19dbf/32.png) [@Mr.Excellent](https://boards.straightdope.com/u/Mr.Excellent)\ **Post date:** [September 30, 2010, 8:24pm UTC](https://boards.straightdope.com/t/five-g-planet/555593/40 "2010-09-30T20:24:03Z")
> [@Stranger\_On\_A\_Train](#): > > > [@Mr.Excellent](#): > > > > I wanna send a probe! This is neat! Heck - if we built a probe on the old “Orion” design (set off nukes behind a giant pusher-plate for acceleration), it’s not crazy to hope we could hit maybe 5% of light-speed. > > [thread=477444]Do we have the technology to build a probe to visit another star?[/thread] > > The answer: not by a long shot. Perhaps some day, but not today, not next year, and probably not for decades (at least 10-20 years of concerted effort). > > Stranger Oh, I know. But 10-20 years of concentrated effort isn’t all that much, in the scheme of things. Again: Cathedrals. Heck, I’d be inclined the name the probe _after_ a cathedral, as a PR point and to suggest the appropriate mind-set. [Previous page](https://boards.straightdope.com/t/five-g-planet/555593.md?page=1) [Next page](https://boards.straightdope.com/t/five-g-planet/555593.md?page=3)